Initial Connection Establishment in a Wireless Communication System

ABSTRACT

A method, user equipment, network equipment and a system for initiating a wireless connection and subsequent communication over a shared physical resource in a wireless communication system between user equipment and network equipment comprising: processing a UE-derived temporary identifier; determining a set of channels that the user equipment will monitor; implicitly or explicitly communicating this channel set; communicating the temporary identifier as an identifier to the network equipment; communicating a downlink message on a channel belonging to the determined channel set conveying the temporary identifier and a description of a scheduled resource on a shared channel, the scheduled resource comprising a resource allocated to the user equipment by the network equipment; and communicating data on the scheduled resource in response to the downlink message.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of U.S.patent application Ser. No. 11/330,820, filed on Jan. 11, 2006, which isa continuation of U.S. patent application Ser. No. 11/325,829, filed onJan. 4, 2006, which is incorporated by reference in its entirety herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to wireless communicationtechnology, and more particularly to an initial connection procedurebetween user equipment and network equipment in a wireless communicationsystem.

2. Description of the Related Art

In wireless communication systems there is the need for a logicalconnection between a mobile station (also referred to as user equipment(UE), a user terminal, a mobile terminal, a wireless data terminal and acellular phone) and radio access network. The radio access network maycomprise one or more base stations (also referred to as a Node B, forexample in 3GPP nomenclature) together with one or more radio networkcontrollers (RNCs). The logical connection provides a context for aparticular network to UE communication link over which data may betransferred without miscommunication of the data to network elements orUEs in the system that are not intended to take part in thecommunication.

In the radio access network system defined by 3GPP, the logicalconnection between the user terminal and the radio access network isdefined by radio resource control (RRC) connection states. Two of themain RRC connection states are defined as RRC connected and RRC idle.

If there is a logical connection between the user terminal and the radioaccess network, then the user terminal is said to be in RRC connectedstate. The existence of a user terminal in RRC connected state can bedetermined within a cell or multiple cells. Therefore, the radioresources for a particular user terminal can be managed efficiently bythe wireless network. In contrast to RRC connected state, a userterminal in RRC idle state has no logical connection to the wirelessaccess network. Thus, the user terminal in RRC idle state can only bedetermined within the core network or area that is larger than the cell,such as a location area or routing area.

When the user terminal is initially switched on by the user, a publicland mobile network (PLMN) is selected and the user terminal searchesfor a suitable cell to be camped on to and remains in RRC idle state inthe corresponding cell. An initial RRC connection may be initiatedeither by the network or by the user equipment. For example, in the caseof a UE initiated connection for a UE in the RRC idle state, the UErequires an initial connection to the network and sends a RRC connectionrequest message to the network. By means of a further example, in thecase of a network initiated connection, an RRC connection requestmessage may also be sent by the UE in response to receipt of a pagingmessage from the network (the network having sent the paging message tothe UE to illicit the commencement of an RRC connection procedure).

There are thus a number of reasons for RRC connection request by the UE.For example: (1) Initial cell access: when the UE attempts to make acall, the UE needs to establish an RRC connection; (2) Paging response:when transmitting a response message to a paging message; (3) Cellupdate: when the UE selects a suitable cell while in idle mode; (4)UTRAN Routing Area (URA) update: when the UE selects a suitable URAwhile in idle mode; and (5) Multimedia Broadcast and Multicast (MBMS)connection: in order to receive MBMS service and request for MBMSpoint-to-point connection.

In the conventional RRC connection procedure, the user terminalinitiates the connection procedure by transmitting a RRC connectionrequest message to the network using common uplink transport channels.The common uplink transport channels are shared by a plurality of UEsand are used for non-scheduled data transmission.

The network considers the connection request and may return on downlinkeither an RRC connection setup message (in the event of a successfuladmission) or an RRC connection reject message (in the event of anunsuccessful admission). In both cases the message is sent using commondownlink transport channels which are (similar to the uplink commonchannels) shared by a plurality of UEs and used for non-scheduled datatransmission.

The common transport channel over which messages from the user terminalto the network are transmitted during this initial RRC connection phaseare termed random access channels. Random access transmission maysimilarly be referred to as unscheduled transmissions, as no explicitscheduling or coordination of the transmissions is carried out. Due tothis lack of explicit coordination, there exists a probability that onemobile will transmit using the same uplink transmission resources oruplink identity as another user. In this instance, the communicationreliability of both transmissions may be compromised due to the mutuallogical or actual interference the uplink messages generate at thereceiving base station. These cases, in which more than one mobiletransmits on a defined set of uplink resources, may be referred to ascollisions.

A further description of collisions, unscheduled access and scheduledaccess may be found in U.S. patent application Ser. No. 11/263,044,filed on Oct. 31, 2005, titled “FREQUENCY DOMAIN UNSCHEDULEDTRANSMISSION IN A TDD WIRELESS COMMUNICATIONS SYSTEM” to inventorNicholas W. ANDERSON, and which is hereby incorporated by reference.

The common downlink transport channels used to convey the correspondingmessages from the network to the user terminal are termed forward accesschannels (FACH).

System resources are typically reserved for these uplink and downlinkcommon transport channels. The radio resources used for common channelsare typically separated from the radio resources used for othertransport channels. Examples of other types of transport channelcomprise dedicated transport channels and shared transport channels. Inthe case of dedicated transport channels the data is mapped to a sub-setof the total radio resources assigned on a long term basis to aparticular user or connection. Conversely, in the case of sharedchannels, the data for each user is more dynamically mapped to a part ofa pool of radio resources assigned within the set of total radioresources under control of a resource scheduler located typically withinthe MAC layer (layer 2) of the network. The radio resource in thisinstance is thus shared amongst users and is arbitrated by thescheduler. This is to be contrasted against the case for common channelsin which the users share the radio resource but in a non-scheduledmanned.

The use of shared channels only can provide benefits in terms of systemcapacity when compared to the use of multiple channel types within thesystem (such as mixtures of common, shared and dedicated types) whereineach is assigned for a particular traffic type. This is because, bymultiplexing all traffic types onto only shared channels, the schedulercan dynamically adapt the resources assigned to the varyinginstantaneous loads presented by each traffic type. In contrast, if forexample we assign one traffic type exclusively to common channels andanother traffic type exclusively to shared channels, then variations inthe traffic loads offered by each traffic type cannot be accommodatedwithout reconfiguring the respective portions of the total radioresource space assigned firstly to common and secondly to sharedchannels. This reconfiguration of radio resources is typically a slowprocess and the system is therefore unresponsive to fast variations inload. A consequence of this is that in current systems, the fraction ofthe total radio resource space assigned to common channels often has tobe designed with a worst-case consideration in mind and radio resourceusage efficiency is therefore suboptimum.

Following a conventional RRC connection establishment procedure, theexistence of the UE is known by the network and a shared channel addressor UE ID may then be assigned by the network only at the completion ofthe connection establishment procedure. Therefore, shared channels mayonly be used after the normal RRC connection procedure has beenaccomplished using the common channel procedures. A significant portionof the total radio resource space must therefore be pre-assigned to thecommon channels to carry the connection establishment traffic. The userterminal specific layer 2 connection context used for the shared channeloperation can only be established at the completion of the RRCconnection procedure.

In addition, known wireless communication systems expend a substantialamount of time and exchange a number of signaling messages on unsharedand common channels to establish an initial layer 2 context for sharedchannel operations and this can contribute to communication delay.Furthermore, the existence of a plurality of channel types andassociated protocols, procedures and attributes can significantlyincrease system implementation complexity.

For the above-mentioned reasons, an improvement to the initial systemaccess and RRC connection procedure is desirable in order to improveradio resource usage efficiency, to reduce communication delay and tosimplify system implementation complexity.

BRIEF SUMMARY OF THE INVENTION

Some embodiments of the present invention provide a prompt establishmentof a layer 2 shared channel context by allowing the UE to derive its ownlayer 2 address as a temporary identifier until the network decides toreplace the UE-derived temporary identifier with a network selectedidentifier and allowing the UE to communicate a set of channels that itwill monitor for downlink messages from the network. This combinationenables the system to utilize shared channels in lieu of common channelsat a very early stage of the connection establishment, helps tominimizes the volume of traffic carried on common channels and alsoassists in conflict avoidance.

Some embodiments of the present invention provide for a method ofinitiating a wireless connection and subsequent communication over ashared physical resource in a wireless communication system between userequipment and network equipment, the method, by the user equipment,comprising: deriving a temporary identifier; deriving a channel set;transmitting an initial message to the network equipment, the initialmessage comprising the temporary identifier; receiving a downlinkmessage on a channel belonging to the derived channel set conveying thetemporary identifier and a description of a scheduled resource on ashared channel, the scheduled resource comprising a resource allocatedto the user equipment by the network equipment; and communicating dataon the scheduled resource in response to the downlink message.

Some embodiments of the present invention provide for one or more of thefollowing options in various combinations: the channel set comprisesmultiple channels; the deriving of the channel set comprises randomlyselecting the channel set from a plurality of channel sets; the derivingof the channel set comprises determining the channel set based on aglobal UE identifier, for example, wherein the global UE identifiercomprises one of a temporary mobile subscriber identity (TMSI), aninternational mobile subscriber identity (IMSI), or an internationalmobile equipment identity (IMEI); the deriving of the channel setcomprises determining the channel set as a function of one or morecharacteristics of a physical resource, and wherein the transmitting ofthe initial message comprises transmitting the initial message on thephysical resource, for example, wherein the characteristic of thephysical resource comprises one or more of a parameter of time, aparameter of frequency, and/or a parameter of a code; the deriving ofthe channel set comprises determining the channel set based on one ormore of a characteristic of a physical resource, a global UE identifier,and the temporary identifier; the initial message further comprises aglobal UE identifier; further comprising determining a physical resourceand wherein the transmitting of the initial message comprisestransmitting the initial message in accordance with the determinedphysical resource; further comprising signaling an indication of thechannel set; further comprising implicitly communicating an indicationof the channel set; the transmitting of the initial message to thenetwork equipment comprises transmitting a scheduling request message;the transmitting of the initial message to the network equipmentcomprises transmitting an RRC connection request message; furthercomprising: timing out after the transmitting the initial message andbefore the receiving of the downlink message; determining a differentphysical resource; and retransmitting the initial message on thedifferent physical resource; and/or wherein the wireless communicationsystem comprises an evolved UMTS Terrestrial Radio Access Network(E-UTRAN).

Some embodiments of the present invention provide for user equipmentused in initiating a wireless connection and subsequent communicationover a shared physical resource in a wireless communication systembetween the user equipment and network equipment, the user equipmentcomprising: a memory; a processor coupled to the memory; and programcode executable on the processor, the program code operable for:deriving a temporary identifier; deriving a channel set; transmitting aninitial message to the network equipment, the initial message comprisingthe temporary identifier; receiving a downlink message on a channelbelonging to the derived channel set conveying the temporary identifierand a description of a scheduled resource on a shared channel, thescheduled resource comprising a resource allocated to the user equipmentby the network equipment; and communicating data on the scheduledresource in response to the downlink message.

Some embodiments of the present invention provide for one or more of thefollowing options in various combinations: the deriving of the channelset comprises randomly selecting the channel set from a plurality ofchannel sets; the deriving of the channel set comprises determining thechannel set as a function of one or more characteristics of a physicalresource, for example time, frequency and code, and wherein thetransmitting of the initial message comprises transmitting the initialmessage on the physical resource; the transmitting of the temporaryidentifier to the network equipment includes transmitting the temporaryidentifier within a first uplink message containing the temporaryidentifier and a request for the scheduled resource; the deriving of thechannel set comprises determining the channel set based on one or moreof a characteristic of a physical resource, a global UE identifier, andthe temporary identifier; the program code is further operable fordetermining a physical resource and wherein the transmitting of theinitial message comprises transmitting the initial message in accordancewith the determined physical resource; and/or the program code isfurther operable for signaling an indication of the channel set, forexample, wherein the program code is further operable for implicitlycommunicating an indication of the channel set.

Some embodiments of the present invention provide for network equipmentused in initiating a wireless connection and subsequent communicationover a shared physical resource in a wireless communication systembetween user equipment and the network equipment, the network equipmentcomprising: a memory; a processor coupled to the memory; and programcode executable on the processor, the program code operable for:receiving an initial message sent by the user equipment; determining achannel set; allocating a scheduled resource to the user equipment, thescheduled resource comprising a resource on a shared channel;transmitting a downlink message on a channel belonging to the determinedchannel set, the downlink message conveying the temporary identifier anda description of the scheduled resource; and communicating data on thescheduled resource in response to the downlink message.

Some embodiments of the present invention provide for: determining thechannel set wherein the determining the channel set comprises extractinga channel indication from the initial message, the channel indicationindicating the channel set; or determining the channel set wherein thedetermining the channel set comprises determining the channel set fromthe physical resource carrying the initial message.

Some embodiments of the present invention provide for a computer programproduct comprising program code for initiating a wireless connection andsubsequent communication over a shared physical resource in a wirelesscommunication system between user equipment and network equipment, thecomputer program product comprising program code for: deriving atemporary identifier; deriving a channel set; transmitting an initialmessage to the network equipment, the initial message comprising thetemporary identifier; receiving on a downlink channel belonging to thederived channel set a downlink message conveying the temporaryidentifier and a description of a scheduled resource on a sharedchannel, the scheduled resource comprising a resource allocated to theuser equipment by the network equipment; and communicating data on thescheduled resource in response to the downlink message.

Other features and aspects of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings which illustrate, by way of example, the featuresin accordance with embodiments of the invention. The summary is notintended to limit the scope of the invention, which is defined solely bythe claims attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The above needs are at least partially met through provision of theINITIAL CONNECTION ESTABLISHMENT IN A WIRELESS COMMUNICATION SYSTEMdescribed in the following detailed description, particularly whenstudied in conjunction with the drawings, wherein:

FIGS. 1A and 1B show a conventional sequence of messages fortransitioning from an RRC idle state to an RRC connected state in aconventional UMTS system.

FIGS. 2, 3A and 3B compare a UTRAN network and an evolved UTRAN(E-UTRAN) network operating with user equipment (UEs) and a core network(CN).

FIGS. 3A and 3B illustrate an evolved UTRAN (E-UTRAN) network operatingwith user equipment and a core network in accordance with the presentinvention.

FIG. 4 shows components of user equipment in accordance with the presentinvention.

FIGS. 5A and 5B show initial signaling sequences in accordance with thepresent invention.

FIGS. 6A and 6B show detailed signaling sequences using a scheduleddownlink in accordance with the present invention.

FIGS. 7A and 7B show detailed signaling sequences using a scheduleddownlink and both non-scheduled and scheduled uplink in accordance withthe present invention.

FIGS. 8A and 8B show detailed signaling sequences using a scheduleddownlink and a scheduled uplink in accordance with the presentinvention.

FIGS. 9 and 10 illustrate processes of contention resolution inaccordance with the present invention.

FIGS. 11 and 12 illustrate processes of contention avoidance andresolution using multiple scheduling grant channels in accordance withthe present invention.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions and/or relative positioningof some of the elements in the figures may be exaggerated relative toother elements to help to improve understanding of various embodimentsof the present invention. Also, common but well-understood elements thatare useful or necessary in a commercially feasible embodiment are oftennot depicted in order to facilitate a less obstructed view of thesevarious embodiments of the present invention. It will further beappreciated that certain actions and/or steps may be described ordepicted in a particular order of occurrence while those skilled in theart will understand that such specificity with respect to sequence isnot actually required. It will also be understood that the terms andexpressions used herein have the ordinary technical meaning as isaccorded to such terms and expressions by persons skilled in thetechnical field as set forth above except where different specificmeanings have otherwise been set forth herein.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings which illustrate several embodiments of the present invention.It is understood that other embodiments may be utilized and mechanical,compositional, structural, electrical, and operational changes may bemade without departing from the spirit and scope of the presentdisclosure. The following detailed description is not to be taken in alimiting sense, and the scope of the embodiments of the presentinvention is defined only by the claims of the issued patent.

Some portions of the detailed description which follows are presented interms of procedures, steps, logic blocks, processing, and other symbolicrepresentations of operations on data bits that can be performed oncomputer memory. A procedure, computer executed step, logic block,process, etc., are here conceived to be a self-consistent sequence ofsteps or instructions leading to a desired result. The steps are thoseutilizing physical manipulations of physical quantities. Thesequantities can take the form of electrical, magnetic, or radio signalscapable of being stored, transferred, combined, compared, and otherwisemanipulated in a computer system. These signals may be referred to attimes as bits, values, elements, symbols, characters, terms, numbers, orthe like. Each step may be performed by hardware, software, firmware, orcombinations thereof.

Though the following figures illustrate the invention with reference toa conventional Universal Mobile Telecommunications System (UMTS system),embodiments of the invention may apply to other wireless radio systemsas well. A conventional UMTS system usually includes multiple userequipment (UE), which are sometimes referred to as user terminals,mobile stations, mobile terminals, wireless data terminals and cellularphones. The conventional UMTS system also includes network equipmentincluding a Node B, also referred to as a base station, which provides aradio access connection between the UEs and the network, and alsoincluding a radio network controller (RNC).

FIGS. 1A and 1B show a conventional sequence of messages fortransitioning from a radio resource connection (RRC) idle state to anRRC connected state in a conventional UMTS system. In a conventionalUMTS system, a UE in an RRC idle state may initiate an RRC connectionthrough a procedure as indicated in FIGS. 1A and 1B. The UE and networkmay exchange messages over logical control channels where each logicalcontrol channel is mapped to a common transport channel.

FIG. 1A shows the messaging exchanged over the air interface (Uu). Thefirst message shown is the RRC connection request message, whichincludes the network-known UE identifier, shown as a global UEidentifier (ID) and an establishment cause. The network-known UEidentifier may be one of the network assigned temporary mobilesubscriber identity (TMSI), the UE's international mobile subscriberidentity (IMSI), or the UE's international mobile equipment identity(IMEI). The establishment cause indicates the reason for the UErequesting a connection with the network. A UE may request a connectionwhen transmitting a response message to a paging message (pagingresponse), when selecting a suitable cell while in idle mode (cellupdate), when selecting a suitable URA while in idle mode (URA update),and when receiving MBMS service or an MBMS point-to-point connection(MBMS connection).

Next, the network performs admission control and allocates Radio NetworkTemporary Identifier (RNTI) values. The network uses an admissioncontrol process to determine whether a requested service from theestablishment cause can be supported by the network. Factors consideredwhen performing admission control may include mobile access class fordetermining privileges, the Radio Resource Management status (RRMstatus) to determine availability of resources, details of the user'ssubscription, and equipment registers including lists of valid andstolen terminals.

The allocation of the RNTI values involves the network allocating aServing Radio Network Controller (RNC) RNTI (S-RNTI), which is used byUE to identify itself to the serving RNC. The S-RNTI is also used by theSRNC to address the UE. An S-RNTI value is allocated by the Serving RNCto each UE having an RRC connection and is unique within the ServingRNC. The S-RNTI may be reallocated after the Serving RNC for the RRCconnection has changed. The S-RNTI may be concatenated with an SRNCidentifier (SRNC ID) received in a broadcast channel to form a uniqueRNTI (U-RNTI) within UTRAN. Optionally, the network may allocate a CellRadio Network Temporary Identifier (C-RNTI). The C-RNTI may be allocatedand used on common transport channels. The C-RNTI value may be used toidentify the UE on a cell basis. In a conventional network, the decisionto use the C-RNTI is made by the Controlling Radio Network Controller(CRNC).

After the network equipment performs a successful admission controlprocess and allocation process, the network responds to the RRCconnection request message with an RRC connection setup messageincluding the global UE ID, the newly-allocated S-RNTI value, optionallya C-RNTI value, and a radio bearer configuration.

Once the RRC connection setup message is processed by the UE, the UEresponds with an RRC connection setup complete message. The RRCconnection setup complete message is accompanied by the C-RNTI value ina header field and includes the UE radio access capability. At thispoint, the UE enters an RRC connected state.

In response to receiving the RRC connection setup complete message, andif the high speed downlink shared channel (HS-DSCH) is to be used fordownlink data transfer, the network may allocate an H-RNTI value to theUE within an RRC radio bearer setup message to the UE. The H-RNTI valueis used to identify the UE on the high speed downlink shared channel.The RRC radio bearer setup message includes the allocated S-RNTI, theallocated H-RNTI and a shared channel radio bearer configuration. The UEcompletes the process by responding with an RRC radio bearer setupcomplete message. At this point, the UE and network have established alayer 2 context for shared channel operations.

FIG. 1B shows elements of the UE and network equipment and the messagingbetween these elements. The UE includes a layer 3 comprising an RRClayer, a layer 2 comprising a Radio Link Control (RLC) layer and amedium access control (MAC) layer, and a layer 1 comprising a physicallayer (L1). The Node B includes a layer 1 physical layer (L1). The RNCincludes a layer 2 comprising a MAC layer and an RLC layer, and a layer3 comprising an RRC layer and an RRM layer. Note additional layer 1functions also exist in both the Node B and the RNC to provide physicalconnections between these entities (lub interface) although these arenot shown for diagrammatical clarity. The RRC connection request messageis initiated by the RRC layer in the UE. The RRC sends a message to theRLC layer which sends the RRC connection request message a commoncontrol channel (CCCH) mapped onto a random access channel (RACH) usingan RLC transparent mode (TM). When using a transparent mode (TM) themessage sender does not include a message sequence identifier unlikeacknowledged mode (AM) and unacknowledged mode (UM), which both includea message sequence identifier that may be used foridentifying/reordering out of sequence packets and for identifyingmissing packets. The acknowledged mode (AM) additionally provides formessage retransmission. The CCCH is a common logical control channelbetween the RLC and MAC layers and the RACH is a common transportchannel between the MAC and L1 layers. The RRC connection requestmessage is transmitted over the air interface (Uu) to the network.

Upon receipt of the RRC connection request message, the Node B's layer 1sends the message on a Random Access Channel (RACH) channel to the MAClayer of the RNC. The RACH channel is a common uplink transport channelused to carry control and data information from a UE over random accessphysical resources which may be shared by a plurality of UEs and areused for unscheduled data transmission. The MAC layer sends the messageto the RLC layer over a CCCH channel. In turn, the RLC layer sends themessage to the RRC layer, which sends the message to the RRM layer foradmission control, allocation of the S-RNTI value, and optionalallocation of the C-RNTI value.

After successful admission control and allocation of the S-RNTI value,the RRM returns the allocated S-RNTI value to the RRC layer, which formsthe RRC connection setup message to be sent in an unacknowledged mode(UM). A C-RNTI, which identifies the UE within the cell, is alsotypically allocated. However, if a dedicated physical channel connectionis to be immediately configured, the C-RNTI may be omitted. The RRCsends the RRC connection setup message to the RLC layer. The RLC layersends the message over a CCCH channel to the MAC layer. CCCH is usedbecause a common RNTI context does not yet exist between the network andthe UE. That is, the network knows the RNTI values but the UE does notknow the RNTI values at this stage. The MAC layer sends the message overa Forward Access Channel (FACH). The FACH channel is a common downlinktransport channel that may be used to carry control and data informationto the UE when the network knows the location cell of the UE. The FACHmay be shared by a plurality of UEs for unscheduled downlink datatransmission. The Node B layer 1 transmits the message to the UE overthe air interface (Uu).

Unfortunately, each UE monitoring the FACH channel decodes each andevery RRC connection setup message and other messages in order todetermine whether the enclosed message was addressed to it. Upon receiptof the RRC connection setup message by the UE, the UE's layer 1 sendsthe message over a FACH channel to its MAC layer, which sends themessage over a CCCH channel to the RLC layer, which in turn sends themessage to the RRC layer of the UE. The UE RRC layer may then inspectthe global ID field contained within the connection setup message todetermine whether or not it matches the UE's own global ID. If not, themessage is discarded. If the IDs match, the message is decoded and theUE registers the assignment of the S-RNTI and possibly the C-RNTIvalues. At this point, the UE now has a dedicated control channel (DCCH)allocated to it.

Next, the UE responds using the RRC connection setup complete message,which is sent using an acknowledge mode (AM) to the network. The RRClayer sends a message to the RLC layer, which uses the DCCH channel tosend the RRC connection setup complete message to the MAC layer. The MAClayer sends the message on a RACH (common transport) channel to thephysical layer (L1), which transmits the message over the air interface(Uu) to the Node B. Data sent on DCCH on common transport channelresources is accompanied by a header field in which the C-RNTI iscontained to distinguish the UE on a cell basis from the plurality ofother UEs using the RACH (common transport) channel in that cell. Fordata sent on dedicated or shared transport channels, no C-RNTI isrequired in the header since user identification/addressing isaccomplished at the physical resource level (the mapping betweenphysical resource and user terminal is known at the physical layer).Once the UE has communicated the RRC connection setup complete message,the UE enters an RRC connected state.

Next, the Node B receives the RRC connection setup complete message overthe air interface (Uu). Its layer 1 sends the message to the RNC's MAClayer using a RACH channel. The MAC layer reads the header (containingthe C-RNTI) and sends the message to the appropriate RLC entity usingthe appropriate DCCH channel. The RLC sends the message to the RRClayer.

The network uses another value to identify a UE when the UE communicatesover a high speed-downlink shared channel (HS-DSCH). This value isallocated by the RRC layer and is designated the HS-DSCH RNTI (H-RNTI)value. The H-RNTI value is used as a temporary identifier while the UEis has an established connection over the HS-DSCH channel. The networksends the allocated H-RNTI value to the UE within a Radio Bearer Setupmessage using a DCCH channel between the RLC and MAC layers, and a FACHchannel between the MAC layer and the UE's layer 1. The Node B transmitsthe message over the air interface (Uu) to the UE. The UE's layer 1sends the message over a FACH channel to its MAC layer, which sends themessage to the RLC on a DCCH channel. The RLC sends the message to theRRC layer, which responds with an RRC radio bearer setup completemessage sent to the network using an RLC acknowledged mode (AM). Thechannel path between the UE's RRC layer and the RNC's RRC layerreplicates the channel path described above for signaling the RRCconnection complete message.

Upon being allocated an H-RNTI, the UE may subsequently utilize the highspeed (hs) downlink shared (transport) channel for downlinkcommunication. Resource allocations for this channel are granted by ascheduler located in a MAC-hs entity in Node-B. The MAC-hs entity canaddress the UE within the cell when making high speed downlink sharedchannel allocations by using the H-RNTI as a UE identifier.

The MAC-hs entity is not shown in the figure as it does not take part inthe connection setup procedure and associated messaging. Messaging usedto establish the RRC connection is not conveyed on shared transportchannels.

At this point, the UE and the network have established and formed alayer 2 shared channel context and the network has allocated a sharedchannel identifier to the UE. In forming this layer 2 context, thenetwork allocated the identifier and exchanged three uplink messages andtwo downlink messages.

According to embodiments of the present invention, a UE derives atemporary identifier (temp ID) to promptly establish a layer 2 contextfor more immediate communication over shared transport channels. Thismore immediate layer 2 context can obviate the need for extensivecommunication over common transport channels and can avoid a need toreserve significant portions of the total available radio resources forcommon channels. Such an assignment is typically slow to reconfigure andhence is not responsive to rapid changes in traffic loads. If the UEderived temporary identifier is unique in the network during theduration of use, the UE may be uniquely identified on the shared channeland data may be communicated via dynamic assignment of shared channelresources rather than via statically-assigned common resources as is thecase in conventional systems. Additionally, the network may update theUE derived temporary identifier during or subsequent to the RRCconnection process.

FIGS. 2, 3A and 3B compare a UTRAN network to an evolved UTRAN (E-UTRAN)network operating with user equipment (UEs) and a core network (CN) inaccordance with the present invention.

FIG. 2 shows multiple UEs and UTRAN network equipment. The UTRAN networkequipment provides a link for the UE to the core network. The UTRANnetwork equipment, also referred to as a Radio Access Network (RAN),includes one or more Radio Network Subsystem (RNS). Each RNS includes aRadio Network Controller (RNC) and one or more Node Bs. For RRCsignaling, the RNC provides RRM, RRC, RLC and MAC signaling layers andthe Node B provides layer 1.

FIG. 3A shows an architecture to implement the invention in accordancewith some embodiments of the present invention. An evolved UTRAN(E-UTRAN) network provides a long term evolution (LTE) platform tosimply the UTRAN architecture and reduce the number of interfacesbetween components. The “evolved” and “E-” designation may be used todistinguish conventional components or elements that may be similar tothe corresponding components or elements of the present invention. TheE-UTRAN network provides a link for the UE to communicate with the corenetwork (CN). The E-UTRAN includes an LTE gateway (LTE GW) coupled toone or more evolved Node Bs (E-Node Bs), which perform functions of boththe Node B and the RNC of FIG. 2. The LTE gateway provides an interfacebetween the core network and the E-Node Bs. For RRC signaling, theE-Node B provides RRM, RRC, RLC, MAC and L1 signaling layers. Here, the“evolved” and “E-” designations have been omitted from some labeledcomponents within the E-UTRAN network for brevity purposes.

FIG. 3B shows an alternate architecture for an E-UTRAN network. The LTEgateway provides an interface between the core network and the E-Node Bsand also provides RRM and RRC layers for RRC signaling. In thisarchitecture, the E-Node B provides RLC, MAC and L1 signaling layers.

The embodiments of FIGS. 3A and 3B provide a MAC layer and an RLC layercollocated with the layer 1 processing, which aides in reducingsignaling latencies. FIG. 3A shows the collection of each of the layersused during the RRC connection establishment procedure, which furtherassists with reducing signal latencies.

FIG. 4 shows components of user equipment in accordance with the presentinvention. User equipment comprises a memory for holding the UE-derivedtemporary identifier, a processor, program code executable to derive theUE-derived temporary identifier and store the identifier into thememory, and a transceiver to communicate with the E-UTRAN networkequipment. The memory may be volatile memory such as RAM or non-volatilememory such as flash (EEPROM). The memory may be a component of the UE'scircuitry or may be on a smart card installed in the UE's housing. Theprocessor may be a reduced instruction set computer (RISC), a generalprocessor, a specialized processor, a gate-logic implemented processor,or the like. The program code may be executable machine code, objectcode, scripts or other computer interpreted or compiled code. Theprogram code may be compressed or uncompressed and may be encoded or notcoded. The transceiver may be a code division multiple access (CDMA)transmitter/receiver pair operating in either a time division duplex(TDD) scheme or frequency division duplex (FDD) scheme.

FIGS. 5A and 5B show initial signaling sequences in accordance with thepresent invention. In each figure, the UE first derives a temporaryidentifier (temp ID). The process of deriving a temporary identifier mayvary among different implementations of the present invention.Derivation of a temporary identifier provides an immediate layer 2context for layer 2 messaging over shared transport channels which arescheduled by the E-MAC entity in E-Node B. Derivation of a temporaryidentifier preferably occurs in a manner to minimize the probability toan acceptable level of two UEs deriving the same temporary identifier.If two UEs derive the same temporary identifier within a cell andattempt to use these during an overlapping period of time, additionalcollision detection and recovery procedures may be implemented.

In some embodiments of the present invention, a UE derives a temporaryidentifier by forming the temporary identifier from a portion of anetwork-known UE identifier. The network-known UE identifier may be oneof the network assigned temporary mobile subscriber identity (TMSI), theUE's international mobile subscriber identity (IMSI), or the UE'sinternational mobile equipment identity (IMEI). The UE may use apredetermined number of the lower significant bits of the TMSI, IMSI orIMEI. For example, if the TMSI is available, a UE may derive the temp IDby using the lower 16 bits of a 32-bit TMSI. If the TMSI is notavailable, the UE may use the lower 16 bits of its 32-bit IMSI. Ifneither the TMSI nor IMSI is available, the UE may use the lower 16 bitsof its 32-bit IMEI.

In some embodiments of the present invention, a UE derives a temporaryidentifier by selecting the temporary identifier from a plurality oftemporary identifiers. The plurality of temporary identifiers maycomprise a subset of possible values of common bit length. For example,the plurality of temporary identifiers may include ⅛.sup.th of thepossible permutations of 16 bits. A network may re-allocate a temporaryidentifier by selection of a value from the remaining ⅞.sup.th possiblepermutations in order to eliminate a possibility of potential conflictwith future UE-derived values. The plurality of temporary identifiersmay be in the form of a table stored in RAM or ROM. In some embodiments,the plurality of temporary identifiers is generated by the UE. In someembodiments, the plurality of temporary identifiers is signaled from thenetwork to the UE. In some embodiments, an indication of the pluralityof temporary identifiers is broadcast over a broadcast channel (BCH)from the network to the UE. In some embodiments, the plurality oftemporary identifiers is saved in non-volatile memory.

In some embodiments the UE-derived temporary identifier may also be afunction of time or radio frame number. The function may vary inaccordance with a pre-determined pattern or one signaled to the UE forexample over a broadcast channel (BCH). Alternatively the variationpattern may contain a random element in its derivation. The use of atime-varying component or a time parameter (such as the system clock,super frame number, radio frame number, sub-frame number, time slotnumber) by the user equipment when deriving the temporary identifier mayadvantageously assist in reducing the probability of two or more usersselecting the same temporary identifier within a given time-frame.

After deriving the temporary identifier, the UE transmits thisUE-derived temporary identifier to the E-UTRAN network in a first uplinkmessage. An initial L2 shared channel context is formed as soon as thenetwork has received the initial temporary identifier; at this stageboth the UE and the network know the value of the temporary identifier.However, this connection may be subject to collision, and a morepermanent connection (without possibility for collision) may be formedonce the network has reassigned a replacement temporary identifier.

Upon receipt of the temp ID, the network allocates a physical resource.An allocated physical resource describes the resources allocated to theUE such as would allow for the UE to correctly encode and transmit orreceive and decode the data message. The description may includeattributes such as: (1) an explicit or relational time of transmission;(2) description of a physical channel resources, such as codes,frequencies, sub-carriers, time/freq codes, and/or the like; (3) aformatting type of the data on the resources; and/or (4) FEC encodingtype, block size, modulation format and/or the like.

This physical resource may be either an uplink resource (as shown inFIG. 5A) or a downlink resource (as shown in FIG. 5B). The networktransmits a first downlink message to the UE including the UE-derivedtemporary identifier as a destination address and also including adescription of the allocated physical resource. Next, the UE and networkcommunicate user traffic data or signaling data (data) over theallocated physical resource.

FIG. 5A shows data being communicated on an uplink scheduled, sharedresource allocated by the network and described in the first downlinkmessage. For uplink data, the UE can only transmit the data after the UEhas received and processed the first downlink message containing thedescription of the allocated physical resource. The UE may initiate thissequence of deriving a temp ID and acquiring an uplink physical resourcewhen the UE intends to send user traffic data or signaling data to thenetwork.

FIG. 5B shows data being communicated on a downlink scheduled, sharedresource allocated by the network and described in the first downlinkmessage. For downlink data, the UE can only receive and process the dataafter the UE has received and processed the first downlink messagecontaining the description of the allocated physical resource. In someembodiments, the first downlink message is carried and received in aburst also containing the second downlink message. In this case, the UEprocesses the received burst to obtain the allocated physical resource.If the allocation indicates that the user traffic data or signaling datais contained in the same burst as the first downlink message containingthe allocation, the UE may re-process the received burst to obtain thesecond downlink message.

A conventional system configures both common and shared channels. Thesegmentation of resources limits the efficient use of the combinedresources. For example, if most traffic at a particular time uses commonchannels, then the shared channels are left idle. Conversely, if mosttraffic is using the configured shared channels, then the commonchannels are left under utilized.

In accordance with some embodiments of the present invention, a minimalset of resources may be assigned for unscheduled messages such as thefirst uplink message of FIGS. 5A and 5B. Uplink messages on this channelmay be limited to short messages containing only the temp ID oralternatively containing the temp ID and an indication of what type ofresource is being requested. Unscheduled downlink channels (e.g., FACH)may be removed from the configured channels since each UE initiatescontact with the network using a layer 2 addressable temp ID. Theremainder of the resources may be dynamically allocated between controlchannel message (e.g., the first downlink message) and user traffic dataor signaling data (i.e., second downlink or uplink message). Such anallocation of resources provides a higher bandwidth system due to themore efficient use of resources.

As shown in FIGS. 6A and 6B, some embodiments of the present inventionutilize a random access channel (RACH) for a first uplink message, ascheduled channel for downlink messages, and a common channel forsubsequent uplink messages. As shown in FIGS. 7A and 7B, someembodiments of the present invention utilize a random access channel(RACH) for a first uplink message and scheduled channels for subsequentdownlink and uplink messages. As shown in FIGS. 8A and 8B, someembodiments of the present invention utilize a random access channel(RACH) for an abbreviated initial uplink message and scheduled channelsfor subsequent downlink and uplink messages.

FIGS. 6A and 6B show detailed signaling sequences using a scheduleddownlink in accordance with the present invention. A UE derives atemporary identifier and sends the temporary identifier in a firstuplink message to the network. In addition to the temp ID, the firstuplink message contains an establishment cause parameter and twooptional parameters: buffer occupancy and a global UE ID. Theestablishment cause and the global UE ID may be the same or similar tothe corresponding parameters described above with reference to FIG. 1A.

The buffer occupancy may be used as an indication of the current pendingdata volume for transmission in the UE's transmission buffer and may beused by a scheduler at Node B to determine the extent of resources togrant for uplink transmission. The buffer occupancy could be a singlebit, a range of quantized values, an absolute value in bytes, or a listof values, for example, one for each of a number of transmission flows,types or priority streams.

The UE may transmit the RRC connection request message using transparentmode (TM). Upon receipt of the RRC connection request message by thenetwork equipment, the network performs admission control (describedabove with reference to FIG. 1A) and allocates a physical resource:either an uplink shared channel (UL-SCH) or a downlink shared channel(DL-SCH) as indicated by the establishment cause parameter. Optionally,the network may also allocate an S-RNTI and a replacement temp ID.

The network transmits a first downlink message containing a downlinkscheduling grant indication including the temp ID to address theparticular UE and a description of the allocated physical resource. Thefirst downlink message may be transmitted on a shared physical controlchannel (SPCCH) monitored my UEs expecting or waiting for possiblescheduling messages. A network may also send a replacement temporaryidentifier. The network may select the replacement temporary identifierfrom a list or table of unique identifiers not selectable by UEs. Suchreplacement temporary identifier insures that a message containing aUE-derived temporary identifier from a first UE will not collide with amessage containing the same temporary identifier derived by a second UE.In effect, the UE-derived temporary identifier provides a limitedduration hopefully-unique identifier that may be replaced by a morecertain network selected unique identifier. The replacement temporaryidentifier may be sent in an RRC connection setup message, or may alsobe contained within the SPCCH grant message.

Upon receipt of the downlink scheduling grant message, UEs decode theshort scheduling message and inspect the temp ID. Only the UE address bythe temp ID needs to decode the longer message sent or to be sent on adownlink shared channel (DL-SCH). Other UEs not addressed by thescheduling grant message need not spend CPU cycles or battery resourcesto decode an RRC connection setup or other long messages to determine ifthe message is directed to it.

The UE identified by the temp ID receives and decodes the messagetransmitted in the allocated physical resource described in the downlinkscheduling grant message. This second downlink message to the UE maycontain a RRC connection setup message transmitted by the network usingunacknowledged mode (UM). The RRC connection setup message mayoptionally contain a replacement temp ID, an allocated S-RNTI value,and/or a global UE ID. If the UE receives a replacement temp ID, it usesthis replacement temp ID as its temporary identifier when signalingmessages with the network. Additionally, the global UE ID may beincluded in this first downlink message if received by the network fromthe RRC connection request message and if a conflict between overlappingtemp IDs is detected by the network. In some embodiments, the global UEID is incorporated explicitly in the message. In other embodiments, theglobal UE ID is used for encoding the downlink message (e.g., CRC).

The contention resolution process of handling conflicts is furtherdescribed below with reference to FIGS. 9 and 10. Furthermore, in someembodiments, a radio bearer configuration may be transmitted to multipleUEs using a broadcast channel (BCH).

Next, the UE responds to receiving and processing the RRC connectionsetup message by preparing and transmitting a RRC connection setupcomplete message using acknowledge mode (AM). If a replacement temp IDwas provided by the network, the UE uses this new value as its temporaryidentifier. The RRC connection setup complete message may also containUE radio access capability parameters indicating various capabilities ofthe UE.

In accordance with the present invention, information contained withinthe conventional RRC radio bearer setup message (FIG. 1A) may bebroadcast on a BCH rather than signaled individually to each UE sincethe information describing a shared channel may be used by multiple UEsin a cell.

FIG. 6B shows elements of the UE and network equipment and the messagingbetween these elements. The UE includes a layer 3 comprising an evolvedRRC (E-RRC) layer, a layer 2 comprising an evolved Radio Link Control(E-RLC) layer and an evolved MAC (E-MAC) layer, and a layer 1 comprisinga physical layer (L1). The E-UTRAN network includes a layer 1 physicallayer (L1), a layer 2 comprising an evolved MAC (E-MAC) layer and anevolved RLC (E-RLC) layer, and a layer 3 comprising an evolved RRC(E-RRC) layer and an evolved RRM (E-RRM) layer.

The RRC connection request message is initiated by the E-RRC layer inthe UE. The E-RRC sends a message to the E-RLC layer which sends the RRCconnection request message a common control channel (CCCH) mapped onto arandom access channel (RACH) using a transparent mode (TM). The CCCH isa logical control channel between the E-RLC and E-MAC layers and theRACH is a common transport channel between the E-MAC and L1 layers. TheRRC connection request message is transmitted over the air interface(Uu) to the network.

Upon receipt of the RRC connection request message, the networkequipment's layer 1 sends the message on a Random Access Channel (RACH)channel to the MAC layer. The MAC layer sends the message to the E-RLClayer over a CCCH channel. In turn, the E-RLC layer sends the message tothe E-RRC layer, which sends the message to the E-RRM layer foradmission control and allocation of the replacement temporary identifierand optionally the replacement S-RNTI value.

After admission control and optional replacement of the temporary ID andoptional allocation of the S-RNTI value, the E-RRM returns the allocatedvalues to the E-RRC layer, which forms the RRC connection setup messageto be sent in an unacknowledged mode (UM). The E-RLC sends the RRCconnection setup message to the E-RLC layer. The E-RLC layer sends themessage over a DCCH or a CCCH channel to the E-MAC layer.

Instead of simply forwarding the RRC connection setup message, the E-MAClayer sends a scheduling grant message over a shared physical controlchannel (SPCCH) to layer 1 for transmission to the UE. The UE's layer 1receives the scheduling grant, which indicates the physical resourcethat will carry the RRC connection setup message. The E-MAC layer alsotransmits, either concurrently or subsequently, the RRC connection setupmessage to layer 1 on the allocated physical resource on the downlinkshared channel (DL-SCH). Layer 1 transmits the RRC connection setupmessage over the air interface (Uu) to the UE. Fortunately, each UEmonitoring the air interface decodes only the short scheduling messagesin order to determine whether the enclosed message was addressed to itrather than the longer RRC connection setup message and other messages.

Upon receipt of the RRC connection setup message by the UE, the UE'slayer 1 sends the message over a DL-SCH channel to its E-MAC layer,which sends the message over a DCCH or CCCH channel to the E-RLC layer,which in turn sends the message to the E-RRC layer of the UE.

Next, the UE responds using the RRC connection setup complete message,which is sent using an acknowledge mode (AM) to the network. The E-RRClayer sends a message to the E-RLC layer, which uses the DCCH channel tosend the RRC connection setup complete message to the E-MAC layer. TheE-MAC layer sends the message on a RACH channel to the physical layer(L1), which transmits the message over the air interface (Uu) to thenetwork. Once the UE has communicated the RRC connection setup completemessage, the UE enters an RRC connected state.

Next, the network receives the RRC connection setup complete messageover the air interface (Uu). Its layer 1 sends the message to the E-MAClayer using a RACH channel. The E-MAC layer sends the message to theE-RLC using a DCCH channel. The E-RLC sends the message to the E-RRClayer.

FIGS. 7A and 7B show detailed signaling sequences using a scheduleddownlink and both non-scheduled and scheduled uplink in accordance withthe present invention. The scheduling and exchange of the RRC connectionrequest message and the RRC connection setup message, as well asadmission control and allocation of resources are as described abovewith reference to FIGS. 6A and 6B. FIGS. 7A and 7B depart from theprevious embodiment by sending subsequent uplink messages on sharedresources.

Specifically, when the UE's E-MAC layer receives the RRC connectionsetup complete message from its E-RLC layer, the UE's E-MAC layer firstsends a scheduling request message on a RACH channel or an evolved RACH(E-RACH) channel. The short scheduling request message requestsallocation of an uplink physical resource from the network. Thescheduling request message is transmitted over the air interface (Uu) tothe network. Upon receipt of the scheduling request message by thenetwork's layer 1, the scheduling request message is forwarded on theRACH channel to the network's E-MAC layer. The E-MAC layer allocates anuplink shared channel (UL-SCH) to the UE and describes the uplinkallocation in a scheduling grant message sent on a shared physicalcontrol channel (SPCCH) from the E-MAC layer to layer 1, then over theair interface (Uu) to the UE's layer 1, which forwards the schedulinggrant message on an SPCCH channel to the E-MAC layer. The E-MAC layerforwards the RRC connection setup complete message to layer 1 on theallocated UL-SCH resource for transmission to the network.

By using a shared, scheduled uplink and/or downlink scheme in accordancewith some embodiments of the present invention, one or more advantagesmay be realized. For example, in some embodiments, shorter messages onthe initial uplink resource may reduce the number collisions at thephysical layer over the air interface. In some embodiments, logicalcollisions (occurring due to a common temporary identifier independentlyderived by two UEs during an overlapping time period) may be overcome bycollision recovery procedures at the UE and/or by collision recoveryprocedures in the network. In some embodiments, resources that wouldotherwise be dedicated to RACH and/or FACH common channels may be eitherreduced or possibly eliminated; thus these resources are available forallocation to other channel traffic types. Thus a more efficient usageof radio resources may be realized when compared to the case in whichmultiple traffic types are not allowed to share the same shared channelresources and instead need to be assigned separate resources. This isbecause, by multiplexing all traffic types onto only shared channels,the scheduler can dynamically adapt the resources assigned to thevarying instantaneous loads presented by each traffic type. In contrast,if separate radio resources are statically assigned to each traffic typethen variations in the traffic loads offered by each traffic type cannotbe accommodated without reconfiguring the respective portions of thetotal radio resource space assigned firstly to common and secondly toshared channels. In some embodiments, signaling latency and responsetime as viewed by the UE may be reduced. In some embodiments, the use ofscheduled channels means that a UE decodes short scheduling messages andno longer needs to monitor and decode each common channel messageaddress to other UEs, which may lead to more efficient use of the UE'sbattery life. Furthermore, in some embodiments, the connection setupsignaling exchange over a high speed channel may occur faster than overa conventional common channel.

FIGS. 8A and 8B show detailed signaling sequences using a scheduleddownlink and a scheduled uplink in accordance with the presentinvention. In the embodiment shown, the initial uplink communication isscheduled as well as subsequent communications. Rather than transmittingan initial message containing the RRC connection request, the UE firstsends a short scheduling request message to request the network allocatean uplink physical resource. The UE derives and includes a temporaryidentifier in the short uplink message. The message may optionallyinclude a buffer occupancy parameter (described above) and a causeparameter. The cause parameter may indicate the reason for the request(e.g., uplink physical resource requested). The network allocates anuplink shared channel (UL-SCH) and transmits a scheduling grant on ashared physical control channel (SPCCH) including the UE-derivedtemporary identity and a description of the UL-SCH. The E-MAC layer ofthe UE receives the uplink scheduling grant message on the SPCCH channeland responds by sending the RRC connection request on the allocatedUL-SCH physical channel. The RRC connection request message is receivedby the network which performs admission control and additional resourceallocation as describe above with reference to FIGS. 7A and 7B.Furthermore, FIG. 8A shows some embodiments may use acknowledged mode(AM) while other embodiments may use unacknowledged mode (UM) whencommunicating either or both of the RRC connection request and RRCconnection setup messages.

FIGS. 9 and 10 illustrate processes of contention resolution inaccordance with the present invention. This contention scenario occurswhen two UEs derive and are using a common temporary identifier. Each UEtransmits an RRC connection request message as described with referenceto FIGS. 5A, 5B, 6A-B, 7A-B or 8A-B. Derivation of a temporaryidentifier preferably occurs in a manner to minimize the probability toan acceptable level of two UEs deriving the same temporary identifier.However, in some embodiments two UEs might derive the same temporaryidentifier within a cell. Therefore, additional collision detection andrecovery procedures may be implemented.

FIG. 9 illustrates a remedy primarily instigated by the UEs. Two UEseach transmit an uplink message to the network using an identicaltemporary identifier (1.sup.st temp ID). The uplink message may be amessage transmitted on a RACH channel or an E-RACH. The message may be ascheduling request message (as shown) or some other message. The networkmay detect the duplicate identical temporary identifier in the twouplink messages. The network may elect to perform no followingprocessing and will allow each UE to time out. After not receiving theexpected downlink response, each UE discards the initially derivedtemporary identifier and derives another temporary identifier (2.sup.ndtemp ID and 3.sup.rd temp ID, respectively). Each UE then retransmitsthe original uplink message using the newly derived temporaryidentifier. Upon receipt of the newer temporary identifier, an initiallayer 2 context is established between the respective UE and the networkfor shared channel operations. The network then responds to each UEhaving a unique temp ID as described above.

FIG. 10 illustrates a remedy primarily instigated by the network. Again,two UEs each transmit an uplink message to the network using anidentical temporary identifier (temp ID). The uplink message may be amessage transmitted on a RACH channel or an E-RACH. The message may bean RRC connection request message (as shown) or some other message. Thenetwork may detect an identical temporary identifier in the two uplinkmessages. In this case, two UEs have derived the same temp ID and mayeach may expect downlink signaling including this temp ID to be addressto it. In such a case, the network may determine that a conflict orcollision has occurred. However, if one or both of the uplink messagesincludes a global UE ID, the UEs may be distinguished from one another.At this point, an initial layer 2 context is established between therespective UE and the network for shared channel operations.

The network may transmit, on a control channel, a scheduling grantmessage allocated a downlink resource. The network may also transmit, ona traffic channel described in the scheduling grant message, a messageincorporating a global UE ID. For example, the network may transmit anRRC connection setup complete message incorporating addressed to the UEsusing the conflicting UE-derived temporary identification. In someembodiments, the network explicitly incorporates the global UE ID in thedownlink message by including the global UE ID as a parameter.Alternatively, the network may incorporate the global UE ID by using theglobal UE ID to encode the downlink message. For example, theincorporating may comprise computing a cyclic redundancy check (CRC)value using the network-known UE identifier. When decoding the downlinkmessage, each UE may use its global UE ID to determine whether theglobal UE ID was incorporated explicitly as a parameter or alternativelyto decode the message to determine whether the previously-transmittedglobal UE ID was used by the network to encode the message.Additionally, the network may respond by allocating a replacement tempID to the UE that transmitted its global UE ID. Once one of the UEsreceives a replacement temp ID, a unique layer 2 context is formed forboth UEs for shared channel operation. The first UE will receive andproperly decode the RRC connection setup message, which is encoded withits UE. The second UE will attempt to decode the RRC connection setupmessage but will fail because the message is encoded with an unknownglobal UE ID causing the second UE to discard the message and return tothe downlink scheduling channel (SPCCH). The second UE will then receivea second downlink scheduling grant message sent by the network. Thesecond UE will then properly receive and decode the RRC connection setupmessage addressed to it. Both UEs may complete the process by respondingwith an RRC connection setup complete message.

FIGS. 11 and 12 illustrate processes of contention avoidance andresolution using multiple scheduling grant channels in accordance withthe present invention. Some systems may configure multiple channels(e.g., multiple SPCCH channels) for communicating scheduling grantmessages from the network to UEs. These channels may be pre-configured,may be defined by a standard, or may be sent to the UE (for example,sent via a broadcast channel or other system control signaling).

A UE may derive or select a subset (i.e., a single channel or multiplechannels) from the configured multiple channels for later monitoring ofscheduling grant messages. The derived subset of channels that a UE willmonitor may be referred to as a channel set. Using an uplink message, aUE may communicate the channel set either explicitly using a parameteror implicitly by use of a particular physical resource. By communicatinga channel set or an indication of a channel set, a network maydifferentiate UEs that happened to have derived the same temporaryidentifier but have fortunately derived different channel sets. FIG. 11illustrates an example of a UE explicitly communicating a channel set toa network by transmitting an initial message containing an indication ofthe channel set. FIG. 12 illustrates an example of a UE implicitlycommunicating a channel set by way of using a particular uplink physicalresource to transmit an initial message to the network.

In FIG. 11, prior to establishing a connection with the networkequipment, a first UE derives a temporary identifier (temp ID) asdiscussed above. The first UE also derives a channel set. That is, theUE selects a scheduling grant channel (SPCCH) that it will monitor forfuture scheduling grant messages. Alternatively, a UE may select morethan one of the configured scheduling grant channels (SPCCHs), thisbeing termed a channel set.

To derive a channel set containing a single channel or multiple channelsthat the UE monitors for scheduling grant messages, a UE may select thechannel set based on one or a combination of the following parameters:(1) the UE's global UE identifier such as its TMSI, IMSI or IMEI; (2)the derived temporary identifier; and (3) one or more characteristics ofthe physical resource the UE will use to transmit the initial message.The characteristics of the physical resource include a time parameter(such as a system clock, super frame number, radio frame number,sub-frame number, time slot number), a frequency parameter (such as afrequency band, channel number or sub-carrier number) and a code (suchas a midamble code, a scrambling code, a channelization code, atime-frequency code or an orthogonal code).

The example shows a first UE deriving a temporary identifier (temp ID)in conjunction with a channel set. The channel set may be a single SPCCHchannel number or a set of multiple SPCCH channel numbers. The channelset may be represented by a channel indication (e.g., channel indication#1). For example, the channel set may be communicated by transmitting achannel indication value that represents an index to a table known toboth the UE and the network. The table entries may represent a singlechannel number or may represent multiple channels from the set ofpossible channels.

Next, the first UE sends an initial message containing both the selectedtemporary identifier and a channel indication to communicate to thenetwork which one or more channels the network should use to sendscheduling grant messages. For example, the initial message may be ascheduling request for scheduled uplink radio resources or an RRCconnection request message sent as a first message during a connectionsetup process on non-scheduled uplink radio resources. In someembodiments, the UE may also send a global UE identifier (such as aTMSI, IMSI or IMEI) for use in conflict detection and resolution asdiscussed above with reference to FIG. 10. Upon receipt of the initialmessage, the network may associate the temporary identifier and thechannel set pair with a particular UE (e.g., the first UE).

The example further shows a second UE initiating a connectionsimultaneously or a short time later. The second UE similarly derives atemporary identifier and a channel set represented by a channelindication (e.g., channel indication #2). For illustrative purposes, theexample shows that the second UE derived the same temporary identifier(temp ID #1) as did the first UE. However, the second UE happens to haveselected a different channel set. The second UE then sends the temporaryidentifier and the channel indication to the network in an initialmessage. Upon receipt of the initial message, the network may associatethe received temporary identifier and channel set pair with the secondUE.

At this point, both UE's are associated with the same temporary ID,however, due to their selection of different and non-overlapping SPCCHchannel sets as indicated in their channel indication parameters,unintended cross communication may be avoided. The first and second UEwill monitor different SPCCH channels, therefore a common derivedtemporary identifier may be used by the network to address both UEs. Thenetwork will address both UEs with the same temporary identifier butwill send a scheduling message to the first UE on one of the channelsindicated by channel indication #1 and will send another schedulingmessage to the second UE on one of the channels indicated by channelindication #2. Hence, each UE will not process a scheduling grantmessage addressed to the other UE.

Thus, a unique shared channel communication context has been formed bythe system for each UE by virtue of the two UEs selecting differentSPCCH channel sets. Communicating a channel indication may notcompletely remove the possibility for contention because two UEs maystill derive the same temporary identifier and the same channel set. Inthis event, the contention resolution procedures discussed above withreference to FIGS. 9 and 10 may be applied within the context of thepresent invention.

As further shown in FIG. 11, the network may communicate data with thefirst UE over a scheduled shared channel using the steps of: (1)receiving a temporary identifier (temp ID #I) and a channel indication(channel indication #1); (2) allocating downlink or uplink sharedchannel resources; (3) determining a scheduling grant channel (channel#1) from the received channel indication; (4) sending a scheduling grantmessage addressed to temp ID #1 over channel #1 and including adescription of the allocated uplink or downlink shared channelresources; and (5) communicating data by transmitting or receiving thedata on the allocated shared channel resources. Similarly, the networkmay simultaneously or substantially simultaneously communicate with thesecond UE over a scheduled shared channel using the steps of: (1)receiving a temporary identifier (temp ID #1) and a channel indication(channel indication #2); (2) allocating downlink or uplink sharedchannel resources; (3) determining a scheduling grant channel (channel#2) from the received channel indication; (4) sending a scheduling grantmessage addressed to temp ID #1 over channel #2 and including adescription of the allocated uplink or downlink shared channelresources; and (5) communicating data by transmitting or receiving thedata on the allocated shared channel resources.

In a similar manner to that described above with reference to FIGS. 6A,7A and 8A, the network may further re-assign a replacement temporaryidentifier to one or both UEs in order that each UE is assigned a uniquetemporary identifier, thus potentially obviating the need for grantchannel restrictions when sending scheduling grant messages to each UE.Furthermore, in some embodiments, the network may allow a UE to use adifferent set of SPCCH channels. For example, the network couldre-assign a unique replacement temporary identifier to the UE andallowing the network to convey scheduling grants of uplink or downlinkshared channel resources on any downlink SPCCH channel.

In FIG. 12, UEs communicate the channel set implicitly. A first UEderives a temporary identifier and derives a physical resource (physicalresource #1) before establishing a connection with the networkequipment. The physical resource may be characterized by its time,frequency and code parameters. In the embodiment shown, a UE maycommunication the channel set implicitly by the very use of the physicalresource. The network may use one or more characteristics of thephysical resource to infer the channel set to be used by the UE.

In some embodiments, the UE may determine a channel set then determineon which physical resource to send an initial message based on thedetermined channel set. In other embodiments, the UE may determine aphysical resource to send an initial message then determine a channelset based on the determined physical resource. The network usescharacteristics of the physical resource used by the UE to determine thechannel set. For example, the time (e.g., time slot) of the initialmessage may indicate to the network that a particular downlinkscheduling channel or set of channels will be monitored by the UE. Uponreceipt of the temporary identifier, the network may associate thetemporary identifier with a particular one or more scheduling grantchannels (SPCCHs) based on one or more characteristics of the physicalresource (physical resource #1). In some embodiments, the association ofthe temporary identifier or a physical resource with an SPCCH channelnumber or a channel set may vary as a function of the time.Alternatively, the association may be based upon a global UE ID receivedwithin an RRC connection request message. Each UE forms the sameassociation between the transmitted temporary identifier and channel setas is formed by the network. This association may be accomplishedsimilarly in both the UE and in the network. The network furtherassociates the temporary identifier and channel set pair with aparticular UE (in this case, the first UE).

Simultaneously or some time later, a second UE is shown to begin aconnection establishment procedure. The second UE derives a temporaryidentifier and transmits an initial message to the network. Upon receiptof the initial message, the network similarly determines the channel setand associates the temporary identifier with one or more particularSPCCH channel numbers based on a characteristic of the physical resource(physical resource #2).

In some embodiments, an association between the temporary identifier andthe implied channel set is based on a periodic function of time. Thus, afinite set of access period instances within the time period spannedbetween the sending of the two initial messages is configured such thatthe association between a temporary identifier and a channel set doesnot repeat. As such, the transmission of temp ID #1 by the second UE ata later time causes its temp ID #1 to be associated with a differentSPCCH channel number of that which is associated with the first UE. Inthe example shown, temp ID #1 is associated with SPCCH channel #1 forthe first UE, whereas temp ID #1 is associated with SPCCH channel #2 forthe second UE. Thus, the network may send scheduling grant messages to aUE using a scheduling grant channel known a priori to both the UE andthe network and may communicate data uniquely with the first and secondUEs over one or more scheduled shared channels as indicated by thescheduling grant messages.

At this point, both UEs are associated with the same temporaryidentifier, however, due to their association with differing SPCCHchannel numbers, unintended cross communication may be avoided asdiscussed above. Thus, a unique shared channel communication context hasbeen formed by the system for each UE, attributed to the fact that theconnection establishments were initiated using different physicalresources and hence the UEs may be associated with different SPCCHs. Insome embodiments, this method completely removes the possibility ofconnection for non-simultaneous access attempts within a given timeperiod. If a plurality of UEs derives a common temporary identifier buteach transmits the initial message on different physical resources, thenconflicts may be avoided if the UEs are reallocated replacementtemporary identifiers. On the other hand, if a plurality of UEs derivesa common temporary identifier and also transmits the initial message onthe same physical resources, then contentions may be experienced andconflicts may be resolved using contention resolution procedures such asdescribed above with reference to FIGS. 9 and 10.

The length of the substantially contention-free access may be a functionof the number of available SPCCH and the length and nature of thepattern describing the association between a temporary identifier andSPCCH channel number. It would therefore be advantageous for the networkto assign unique replacement temporary identifiers to each UE accessingthe system before the association pattern repeats in time. Thus, bydesigning the association pattern to have a length commensurate with themaximum expected time required to assign a replacement temporaryidentifier, the efficiency of the scheme may be optimized.

While the invention has been described in terms of particularembodiments and illustrative figures, those of ordinary skill in the artwill recognize that the invention is not limited to the embodiments orfigures described. For example, many of the embodiments described aboveare referenced to 3GPP systems and evolved UMTS Terrestrial Radio AccessNetwork (E-UTRAN) nomenclature. More generally, some embodiments mayinclude a transceiver using a code division multiple access (CDMA)transmitter/receiver pair operating in either a time division duplex(TDD) scheme or frequency division duplex (FDD) scheme. Alternatively,the transceiver may be a non-code division transceiver, such as used ina TDMA system, an FDMA system, an OFDM system or hybrids thereof (e.g.TMDA/FDMA, TDMA/CDMA, TDMA/OFDM, and TDMA/OFDM/CDMA). The transceivermay operate on bursts or may operate on a signal stream.

The figures provided are merely representational and may not be drawn toscale. Certain proportions thereof may be exaggerated, while others maybe minimized. The figures are intended to illustrate variousimplementations of the invention that can be understood andappropriately carried out by those of ordinary skill in the art.Therefore, it should be understood that the invention can be practicedwith modification and alteration within the spirit and scope of theappended claims. The description is not intended to be exhaustive or tolimit the invention to the precise form disclosed. It should beunderstood that the invention can be practiced with modification andalteration and that the invention be limited only by the claims and theequivalents thereof.

1. A method of initiating a wireless connection and subsequentcommunication over a shared physical resource in a wirelesscommunication system between user equipment and network equipment, themethod, by the user equipment, comprising: deriving a temporaryidentifier to be used by the network equipment to address the userequipment; deriving a channel set of at least one downlink channel forthe user equipment to receive communications from the network equipment;transmitting an initial message to the network equipment, the initialmessage conveying the temporary identifier and a channel indication;receiving a downlink message using the channel set, wherein the channelset is based on the channel indication, wherein the downlink messageconveys the temporary identifier and a description of a scheduledresource on a shared channel, the scheduled resource comprising aresource allocated to the user equipment by the network equipment; andcommunicating data on the scheduled resource in response to the downlinkmessage.
 2. The method of claim 1, further comprising determining aphysical resource having a characteristic comprising a time, frequencyor code parameter, and wherein the step of transmitting the initialmessage to the network equipment comprises transmitting the initialmessage on the physical resource.
 3. The method of claim 1, wherein thestep of deriving a temporary identifier to be used by the networkequipment to address the user equipment comprises selecting thetemporary identifier from a plurality of temporary identifiers based oninformation received by the user equipment from the network equipment.4. The method of claim 1, wherein the description of a scheduledresource comprises an allocation of at least one of an uplink ordownlink shared physical resource.
 5. The method of claim 1, wherein thechannel indication is conveyed implicitly by use of a particularphysical resource.
 6. The method of claim 1, wherein deriving thechannel set is performed before transmitting the initial message.
 7. Themethod of claim 1, wherein deriving the channel set comprisesdetermining the channel set as a function of one or more characteristicsof a physical resource.
 8. The method of claim 1, wherein the downlinkmessage is received using the channel set wherein the channel setcomprises multiple channels that the user equipment monitors for thedescription of the scheduled resource on the shared channel.
 9. A userequipment used in initiating a wireless connection and subsequentcommunication over a shared physical resource in a wirelesscommunication system between the user equipment and network equipment,the user equipment comprising: a memory having executable program codestored therein; and a processor coupled to the memory; wherein theprogram code, when executed by the processor, is operable for: derivinga temporary identifier to be used by the network equipment to addressthe user equipment; deriving a channel set of at least one downlinkchannel for the user equipment to receive communications from thenetwork equipment; transmitting an initial message to the networkequipment, the initial message conveying the temporary identifier and achannel indication; receiving a downlink message using the channel set,wherein the channel set is based on the channel indication, wherein thedownlink message conveys the temporary identifier and a description of ascheduled resource on a shared channel, the scheduled resourcecomprising a resource allocated to the user equipment by the networkequipment; and communicating data on the scheduled resource in responseto the downlink message.
 10. A user equipment used in initiating awireless connection and subsequent communication over a shared physicalresource in a wireless communication system between the user equipmentand network equipment, wherein the user equipment is configured to:derive a temporary identifier to be used by the network equipment toaddress the user equipment; derive a channel set of at least onedownlink channel for the user equipment to receive communications fromthe network equipment; transmit an initial message to the networkequipment, the initial message conveying the temporary identifier and achannel indication; receive a downlink message using the channel set,wherein the channel set is based on the channel indication, wherein thedownlink message conveys the temporary identifier and a description of ascheduled resource on a shared channel, the scheduled resourcecomprising a resource allocated to the user equipment by the networkequipment; and communicate data on the scheduled resource in response tothe downlink message.
 11. The user equipment of claim 10, wherein theuser equipment is further configured to determine a physical resourcehaving a characteristic comprising a time, frequency or code parameter,and wherein the user equipment is configured to transmit the initialmessage to the network equipment by transmitting the initial message onthe physical resource.
 12. The user equipment of claim 10, wherein theuser equipment is configured to derive a temporary identifier to be usedby the network equipment to address the user equipment by selecting thetemporary identifier from a plurality of temporary identifiers based oninformation received by the user equipment from the network equipment.13. The user equipment of claim 10, wherein the description of ascheduled resource comprises an allocation of at least one of an uplinkor downlink shared physical resource.
 14. The user equipment of claim10, wherein the channel indication is conveyed implicitly by use of aparticular physical resource.
 15. The user equipment of claim 10,wherein the user equipment is configured to derive the channel set bydetermining the channel set as a function of one or more characteristicsof a physical resource.
 16. The user equipment of claim 10, wherein theuser equipment is configured to receive the downlink message using thechannel set wherein the channel set comprises a single channel ormultiple channels that the user equipment monitors for the descriptionof the scheduled resource on the shared channel.
 17. A network equipmentused in initiating a wireless connection and subsequent communicationover a shared physical resource in a wireless communication systembetween user equipment and the network equipment, wherein the networkequipment is configured to: receive an initial message sent by the userequipment wherein the initial message conveys a temporary identifierderived by a user equipment to be used by the network equipment toaddress the user equipment and a channel indication; allocate ascheduled resource to the user equipment, the scheduled resourcecomprising a resource on a shared channel; transmit a downlink messageusing a channel set derived by the user equipment based on the channelindication, the downlink message conveying the temporary identifier anda description of the scheduled resource; and communicate data on thescheduled resource.
 18. The network equipment of claim 17, wherein thetemporary identifier is selected from a plurality of temporaryidentifiers by the user equipment based on information transmitted tothe user equipment by the network equipment.
 19. The network equipmentof claim 17, wherein the description of a scheduled resource comprisesan allocation of at least one of an uplink or downlink shared physicalresource.
 20. The network equipment of claim 17, wherein the channelindication is conveyed implicitly by use of a particular physicalresource.
 21. The network equipment of claim 17, wherein the networkequipment is configured to derive the channel set by determining thechannel set based on the channel indication.
 22. The network equipmentof claim 17, wherein the network equipment is configured to transmit thedownlink message using the channel set wherein the channel set comprisesa single channel or multiple channels that the user equipment monitorsfor the description of the scheduled resource on the shared channel. 23.A method of initiating a wireless connection and subsequentcommunication over a shared physical resource in a wirelesscommunication system between user equipment and network equipment, themethod comprising, at the network equipment: receiving an initialmessage sent by the user equipment wherein the initial message conveys atemporary identifier derived by a user equipment to be used by thenetwork equipment to address the user equipment and a channelindication; allocating a scheduled resource to the user equipment, thescheduled resource comprising a resource on a shared channel;transmitting a downlink message using a channel set derived by the userequipment based on the channel indication, the downlink messageconveying the temporary identifier and a description of the scheduledresource; and communicating data on the scheduled resource.
 24. Themethod of claim 23, wherein the temporary identifier is selected from aplurality of temporary identifiers by the user equipment based oninformation transmitted to the user equipment by the network equipment.25. The method of claim 23, wherein the description of a scheduledresource comprises an allocation of at least one of an uplink ordownlink shared physical resource.
 26. The method of claim 23, whereinthe channel indication is conveyed implicitly by use of a particularphysical resource.
 27. The method of claim 23, wherein the channel setis identified based on the channel indication.
 28. The method of claim23, wherein the downlink message is transmitted using the channel setwherein the channel set comprises a single channel or multiple channelsthat the user equipment monitors for the description of the scheduledresource on the shared channel.
 29. A control circuit for use in userequipment used in initiating a wireless connection and subsequentcommunication over a shared physical resource in a wirelesscommunication system between the user equipment and network equipment,the control circuit being configured to: derive a temporary identifierto be used by the network equipment to address the user equipment;derive a channel set of at least one downlink channel for the userequipment to receive communications from the network equipment; transmitan initial message to the network equipment, the initial messageconveying the temporary identifier and a channel indication; receive adownlink message using the channel set, wherein the channel set is basedon the channel indication, wherein the downlink message conveys thetemporary identifier and a description of a scheduled resource on ashared channel, the scheduled resource comprising a resource allocatedto the user equipment by the network equipment; and communicate data onthe scheduled resource in response to the downlink message.
 30. Thecontrol circuit of claim 29, wherein the control circuit is furtherconfigured to determine a physical resource having a characteristiccomprising a time, frequency or code parameter, and wherein the controlcircuit is configured to transmit the initial message to the networkequipment by transmitting the initial message on the physical resource.31. The control circuit of claim 29, wherein the control circuit isconfigured to derive a temporary identifier to be used by the networkequipment to address the user equipment by selecting the temporaryidentifier from a plurality of temporary identifiers based oninformation received by the user equipment from the network equipment.32. The control circuit of claim 29, wherein the description of ascheduled resource comprises an allocation of at least one of an uplinkor downlink shared physical resource.
 33. The control circuit of claim29, wherein the channel indication is conveyed implicitly by use of aparticular physical resource.
 34. The control circuit of claim 29,wherein the control circuit is configured to derive the channel set bydetermining the channel set as a function of one or more characteristicsof a physical resource.
 35. The control circuit of claim 29, wherein thecontrol circuit is configured to receive the downlink message using thechannel set wherein the channel set comprises multiple channels that theuser equipment monitors for the description of the scheduled resource onthe shared channel.